Aircraft instrument light supporting means



Oct. 28, 1969 o. A. BRISTOL AIRCRAFT INSTRUMENT LIGHT SUPPORTING MEANS Filed July 6, 1967 FIG. 2

INVENTOR DAVID A. BRISTOL ATTORNEY United States Patent Olfice 3,475,602 Patented Oct. 28, 1969 US. Cl. 2402.1 Claims ABSTRACT OF THE DISCLOSURE An instrument lighting arrangement. Aligned apertures through an exposed flange and an interior plate support an elongated, integral lighting fixture. A finger grip and gasket-retaining portion normally located at the flange to facilitate axial displacement of the lighting fixture is bendable to expose a lamp and socket when the fixture is displaced. Optional detent means orient the fixture and limit its axial motion.

BACKGROUND OF THE INVENTION This invention relates to illuminated instruments and more particularly to illuminated aircraft instruments with means for facilitating lamp removal.

Aircraft instrument indicating dials are normally lighted by some integral lamp arrangement. Such illuminated aircraft instruments are usually mounted in a cluster on a panel and are relatively inaccessible for maintenance or repair unless the instruments are removed from the panel. In many applications lamps used to illuminate the dial face of the instrument age and produce less light so that lamp replacement in such instruments is a relatively frequent occurrence. In prior art illumination arrangements, difiiculties have been encountered in providing lamp removal. In some lighting schemes it was necessary to remove and disassemble the instrument to gain access to the lamp. Other lighting schemes required the removal of small parts, which were easily dropped and lost.

Therefore, an object of this invention is to provide an instrument lighting arrangement which facilitates lamp replacement.

Another object of this invention is to provide a lighting arrangement which is integral with the instrument.

Still another object of this invention is to provide a lighting arrangement in an instrument which permits replacement of lamps without disassembling or separating parts from the instrument.

SUMMARY In accordance with one embodiment of this invention, a lamp is removed from an instrument by first pulling an accessible finger grip extension of a lamp fixture which projects in front of the flange to axially displace the lamp fixture. Removal of the fixture axially through the front flange exposes the lamp; and, in accordance with this invention, the finger grip portion can be displaced radially to permit access to and replacement of the lamp without disassembling any portion of the instrument or lamp fixture.

This invention has been pointed out with particularity in the appended claims. Still further objects and advantages of this invention may be understood better by referring to the following description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 shows an instrument having lighting means formed in accordance with this invention for mounting to a panel;

FIGURE 2 is a detailed view of lighting means formed in accordance with this invention;

FIGURE 3 is another detailed view of a lighting means formed in accordance with this invention and shown in FIGURE 2;

FIGURE 4 is yet another detailed view of a lighting means formed in accordance with this invention and taken along the lines 44 in FIGURE 3;

FIGURES 5 and 6 illustrate how a lighting means formed in accordance with this invention is mounted to an instrument such as that shown in FIGURE 1; and

FIGURE 7 illustrates how a lighting means formed in accordance with this invention facilitates removal and replacement of lamps.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGURE 1 illustrates a typical instrument used for panel mounting. Only one instrument 11 is depicted for purposes of clarity. However, in normal applications a plurality of instruments are closely clustered on a panel. This, in combination with normal panel-to-supportingframe mounting arrangements, causes removal of an individual instrument from the panel for maintenance to be a diflicult and time-consuming task.

The operating mechanism for such an instrument is disposed behind a panel and is enclosed by a rearwardly extending housing 12. Indications of measured parameters are provided on an indicating scale 13 by a pointer 14. Usually the indicating scale 13 and the pointer 14 are spaced behind a transparent plate 15 which is supported by a flange 16. The flange 16 abuts against a panel. In most applications it is desired to illuminate the indicating scale 13, and for that purpose lighting means are provided. In FIGURE 1, for example, two lighting fixtures 17 are shown which, as will become evident hereinafter, illuminate the indicating scale 13.

As shown in FIGURES 2, 3, and 4, in a preferred embodiment of a light fixture, this invention comprises an elongated integral body 18 which has a central portion 19 having a plurality of longitudinal apertures 20 formed therethrough to capture terminals for a lamp 21, which are inserted axially from one side of the central portion 19, and conductors 22, which extend axially from the other 'side of the central portion 19.

The lamp 21 is partially surrounded by a pliant portion 23 which integrally connects a first end portion 24 to the central portion 19. The first end portion 24 includes a grooved member 25 which serves as a finger grip portion. Also included in the first end portion 24 is a seat 26 for a gasket 27. The first end portion 24 is cylindrical in cross-section and generally has the same radius as the central portion 19.

Extending axially from the other end of the central portion 19 is a second end portion 30 which has a channel section 31 disposed about the conductors 22. Also, the channel section 31 serves as a base or support for a detent assembly 32 which includes first and second stop members 33 and 34, first and second detents 35 and 36, and-a central detent portion 37. As shown in FIGURE 4, the C-shape of the channel section 31 produces a radial force for the detent assembly 32 when it is deflected.

FIGURES 5 and 6 show how the lighting fixture 17 can be axially displaced with reference to the instruments. These views are taken looking in the same direction as FIGURE 3. The lighting fixture 17 is located in aligned apertures 40 and 41 formed in a flange plate 42 and a parallel spaced plate 43, respectively. The plate 43 is normally rigidly supported from the instrument housing and has a keyed slot assembly to coact with the detent assembly 32. The dashed portion 44 denotes the position of an indicating scale in reference to the flange plate 42. In FIGURE 5, therefore, the lighting fixture 17 is disposed between the flange plate 42 and the plane of the scale portion, dashed portion 44, so that the scale portion is illuminated. In this position the gasket 27 seals the aperture 40 so that light from the lamp 21 does not escape through the flange plate 42. Additionally, the gasket seals dust and moisture from the internal portions of the instrument. The lighting fixture 17 is held in position by the coaction between the spaced plate 43, the first detent 35, and the first stop 33 on the second end portion 30.

If it is desired or necessary to replace the lamp 21, the finger grip portion constituted by the grooved member 25' is pulled axially away from the instrument housing, causing the plate 43 and the first detent 35 to disengage. The lighting fixture 17 is then axially displaced until the plate 43 engages the second stop 34 and the second detent 36. As the portion 23 is pliant, due to its relieved nature and construction, it is possible to manually push the grooved member 25 aside as shown in FIGURE 7 to thereby expose the lamp 21. The lamp 21 can then be easily removed. In this embodiment it is accomplished merely by axially withdrawing the lamp. Upon replacement of the lamp 21, the lighting fixture 17 is moved back to the position shown in FIGURE wherein the plate 43 engages the stop 33 and the detent 35.

In each figure the pliant portion 23 tapers from the central portion 19 to the first end portion 24. In other approaches, a uniform member can be formed. It has been found, however, that with certain materials, tapering improves stress distribution through the lighting fixture caused by displacing the first end portion and thereby lengthens its life.

Several modifications of this device are possible without departing from the scope of the invention. For example, to maintain the orientation of the lamp assembly with respect to the instrument, the detent portion is shown as being adapted to slide in a keyed slot. In some applications the detent assembly or other orientation means might not be necessary.

The first end portion 24 could be made of either a translucent or opaque material. If it is opaque, light transmission is limited to the scale portion of the instrument. However, if the first end portion 24 is formed of a translucent material, the assembly can be adapted to serve as an indicating or alarm lamp for the instrument. It will also be obvious that any number of materials can be used to form the lighting fixture 17; two preferred materials are nylon and Lexan. As will also be obvious, any lamp and socket arrangement can be adapted to use this invention.

Therefore, it is the intent of the appended claimsto cover all modifications which come within the true SPlI'lll and scope of this invention. Incorporation of a lightmg fixture having a pliant portion and an axially displaceable mounting arrangement provides an integral lighting fixture which facilitates bulb replacement. It is not necessary to remove the instrument nor any part thereof.

What is claimed as new and desired to be secured by Letters Patent of the United States is: t

1. In an instrument having an accessible flanged indicator member with an indicating scale and adapted to be located against an instrument panel, an inaccessible spaced parallel plate, aligned apertures formed in the flanged indicator member and plate, lighting means for illuminating the indicating scale, an integral lighting fixture for the lighting means including an elongated body portion extending through and axially slideable in the apertures through said flanged member and sald plate, said integral lighting fixture comprising:

(a) a first, relieved portion partially surrounding said lighting means and normally located to position the lighting means internally of said instrument relative to the indicating scale, said first portion being pivotally connected to said body portion; and

(b) means for providing external access to said lighting means by axially sliding said elongated body member including a second portion integral with said first portion and normally located externally of said flanged indicator member for axially displacing said elongated body portion and positioning said relieved portion and said lighting means external of said instrument and for bending said first and second portions to facilitate access to the lighting means, and

(0) means associated with said elongated body for limiting the axial travel of said elongated body.

2. An instrument lighting fixture as recited in claim 1 wherein said first portion constitutes a sector of an annular member partially surrounding the lighting means, the lighting means including a generally cylindrical bulb, said first portion being integral with said body portion and being pliant to permit access to the lighting means.

3. An instrument lighting fixture as recited in claim 2 wherein said first portion is tapered from said body portion to said second portion.

4. An instrument lighting fixture as recited in claim 2 wherein said second portion constitutes an end for said first portion, said second portion being axially spaced from said body portion to normally prohibit axial bulb movement of said bulb.

5. An instrument lighting fixture as recited in claim 4 wherein said second portion includes manual gripping means and gasket-retaining means and additionally comprises a gasket in said gasket-retaining means for sealing said lighting means against the flanged indicator member.

6. An instrument lighting fixture as recited in claim 5, said gripping means being opaque.

7. An instrument lighting fixture as recited in claim 5, said gripping means being translucent.

8. An instrument lighting fixture as recited in claim 5 wherein said body portion comprises a third portion integral with said first portion having means for supporting a lamp socket and bulb, conductor means extending from said third section.

9. An instrument lighting fixture as recited in claim 8 additionally comprising a fourth section extending axially from said third section including detent means adapted to coact with the spaced plate to limit axial motion of the lighting fixture.

10. An instrument light means as recited in claim 9 wherein said fourth section is generally C-shaped to provide spring deflection forces for said detent means.

References Cited UNITED STATES PATENTS 1,653,418 12/1927 Sorgius 240-816 1,668,522 5/1928 Zubaty 240-8.16 1,798,049 3/1931 Urfer 240--8.16 2,789,206 4/ 1957 Levan et al. 240-2.1

NORTON ANSHER, Primary Examiner W. A. SIVERTSON, Assistant Examiner US. Cl. X.R. 2408.16 

